Screening apparatus



Nov. 29, 1927.

1,650,896 R. A. LEAHY S GREEN IN G APPARATUS Filed Dec. 8, 1923 INVENTOR P, Zcffy- I By @Awfl W aATTOR/Y atented Nov. 2'29, 1927.

STATES RICHARD A, LEAHY, OF BONN E TERRE, MISSOURI.

SCREENING APPARATUS.

Application filed December 8, 1923. Serial No. 679,468.

This invention relates to apparatus of the kind that is used for screening granular material, and particularly, to apparatus of thetype in which thematerial being hair 5 dld is deposited on a screening member which is agitated, vibrated or reciprocated to efieot the separation of the different sized particles of the material.

The main object of my invention is to provide a novel means for actuating the screening medium of a screening apparatus of the type mentioned.

To this end I propose to use a pulsating or vibrating column of liquid to vibrate,

5 agitate or reciprocate a screening member on which granular material is deposited to cause the particles of said material to be stratified and screened.

Figure l of the drawings is an end elevational view of a screening apparatus constructed in accordancewith myinvention; and

Figure 2 is a sectional view of said apparatus, taken at right angles to Figure 1 on the section line 2-2 of Figure 1.

The apparatus herein illustrated is equipped with two screens of identical construction, each of which comprises a screening medium or perforated member A held under to tension and arranged in such a way that it will vibrate between two fixed lines of support, thereby causing the granular material that is deposited on said screening medium to be agitated. Instead of actuating the an screening medium by a cam struck by a tappet directly connected to the screening medi' um, as is the usual practice in this art, I actuate the screening medium A by a means that comprises a pulsating 0r vibrating to column of liquid. In the form of my invention herein shown the pulsating or vibrating column of liquid is used in conjunction with a spring or other resilient elements to im-. part a differential vibrating motion to the at screening medium A of each screen, but I do not wish it to be understood that my broad idea is limited to an apparatus of the particular construction herein shown. This is advantageous, in that it enables a battery as of screens located in proximity to each other or at widely separatedpoints to be operated by a single sourcev of power.

In the form of my invention herein illustrated each of the screens is equipped with at a reciprocating actuating device B connected at one end to the screening medium A of the screen, and having its opposite end arranged in an open-ended cylinder C that communt cates with the interior of a pipe D that contains a column of liquid that is used to impart a slow movement in one direction to the actuating members B of all the screens. Each of said actuating devices B is subjected to a quick or sudden movement/in the opposite direction by. means of a spring or other suitable resilient element E so as to cause a collar 1 on said actuating device to strike against a stationary abutment or tappet block 2 carried by a yoke 3 that serves as a guide for the actuating device B and which is arranged transversely of the screening medium A of the screen at a point above same, as shown in Figure 1. Any suitable means can be used for causing the column of liquid in the pipe D to exert pressure on the actuating devices B of the screens in a direction to place the springs E under tension, but I prefer to equip the apparatus With a rotatable cam F that acts upon a plunger G which is reciprocatingly mounted in a cylinder H from which the pipe D leads, the cam F being operated by an electric motor I or other suitabledriving means. The rotary movement of the cam F depresses the plunger G, thereby causing the column of liquid in the pipe D to act on the actuating devices B in such a way as to impart a slow downward movement to the screening medium A of each screen. When said plungeris released by the revolution of the cam the actuating device B of each screen is forced upwardly suddenly by the spring E associated with same, thus causing the collar 1 on the actuating device to strike against the tappet block 2, whereupon the upward movement of the screening medium A will he suddenly arrested and the granular material thereon will be subjected to such action as to cause the heaviest particles of the material to be moved upwardly into a position where they Will not obstruct the passage of the liner particles of the material through the screening medium. This action, in addition to causing the particles of the material to be stratified according to their relative masses or sizes, tends to prevent the openings or meshes of the screening medium A from becoming clogged by particles of material sticking in same, because the blow which the screening medium is subjected to when the upward movement of said screening medium is suddenly arrest:

ed is sufficient to dislodge the particles that stick in the meshes of the screening medium.

The particular construction and arrangement of the screening medium A is immaterial, so far as my broad idea is concerned, but I prefer to construct said screening medium from flexible material having meshes therein and held under longitudinal tension between two iixed points, such, for example, as a top cross member a to which the upper end of the screening medium A is connected and a bottom cross member 5 connected to the lower end of the screening medium and combined with adjusting devices (5 that can be manipulated to vary the tension of the screening medium, such a construction being desirable because it permits the side edges of the screening medium A to vibrate freely. It is also immaterial how the actuating device B is connected to the screening medium A, but in most instances the lower end of said actuating device B will he joined to a rigid member J connected to the screening medium A and arranged intermediate the pointsv between which said screening medium vibrates.

As previously stated, my broad idea consists of a screening apparatus composed of a screening medium, and a mechanism for actuating said screening medium comprising a pulsating or vibrating column of liquid. So far as said broad idea is concerned, it is immaterial whether said mechanism comprises a resilient element for moving the screening medium in one direction and a pulsating or vibrating column oi liquid for moving said screening medium in the opposite direction, or whether said mechanism comprises two separate and distinct pulsating or vibrating columns of liquid, one of which columns is used for moving the screening medium in one direction and the other is used for moving said screening medium in the opposite direction. Another modification thatmight be made without departing from the spirit of my invention is to construct the screening medium in such a way that it has suiiicient inherent resiliency to maintain it in a certain position and use a pulsating or vibrating column of liquid to flex said screening medium in one direction, depending upon the resiliency of the screening medium to move said screening medium in the opposite direction. Still another change that might be made without departing from my broad ideais to use diaphragms instead of pistons to act on the column of liquid. In such a structure the cylinder H and cooperating plunger G will be replaced by a flexible diaphragm connected to or arranged to act upon a tappet that co-operates with the cam F, and the cylinder C and recipro- 1 eating actuating device 13 would be replaced by a flexible diaphragm connected to or arranged to act upon a tappet rod secured to the rigid member arranged transversely ol" the screening medium.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An apparatus of the kind described, comprising a plurality of screening mem bers, each of which is adapted to have granular material deposited thereon, a springpressed actuating device associated with each of said members, a column of liquid that is adapted to act on all of said actuating devices, and a means for causing said column of liquid to exert pressure on said actuating devices intermittently in op osi tion to the springs associated with suit devices.

2. A screening apparatus, comprising a screening medium, means comprising a column of liquid for imparting a slow movement to said screening medium in one direction, and a resilient means for thereafter imparting a quick movement to said screening medium in the opposite direction and suddcnly arresting the movement of said screening medium.

A screening apparatus, comprising a screening medium, an actuating device associated with said screening medium, a resilient element that normally opposes the movement of said actuating device in one direction, and mean for causing a column of liquid to act on said device intermittently in opposition to said resilient element.

4. A screening apparatus, comprising a screening medium, an actuating device associated with said screening medium, a resilient element that opposes movement of said actuating device in one direction, a column of liquid arranged so as to act on said actuating device, and means for causing said column of liquid to pulsate or vibrate.

A screening apparatus, comprising a. screening medium, an actuating device associated with said screening medium, a resilient means that opposes movement of said actuating device in one direction, a column or" liquid arranged so as to act on said actuating device, a plunger that exerts pressure on said column of liquid, and a rotatable device that strikes said plunger intermittently.

6. A screening apparatus, comprising a flexible screening medium held under tension and adapted to have granular material deposited thereon, an actuating device conncctedto a rigid member that is fastened to said screening medium intermediate the points between which it vibrates, a resilient means tl at opposes the movement of said actuating device in one direction, and means for causing a column of liquid to pulsnte or vibrate and act on said actuating device in opposition to said sprin 7. A screening apparatus, comprising a flexible screening medium held under tension and adapted to have granular material deposited thereon, an actuating device connected with a rigid member that is fastened to said screening medium intermediate the points between which it vibrates, a resilient element that opposes the movement of said actuating device in one direction, a stationary tappet block that co-operates with a part on said actuating device to suddenly l0 arrest the movement of said device when it is moving under the influence of said resilient element, a column of liquid arranged so that it will act on said actuating device,

and means for causing said column of liquid 1 to pulsate or vibrate.

RICHARD A. LEAHY. 

